Vacuum-sealed chamber for coating-stripping solution



Apr-i1 14, 1964 P. woRRELL VACUUM-SEALED CHAMBER FOR COATING-STRIPPING SOLUTION Filed Oct. 26. 1962 INVENTR. LOU/S l? WORRELL @y Altar/ley United States Patent Olitice 3,128,780 Patented Apr. 14, 1964 3,128,780 VACUUM-SEALED CHAMBER FUR COATING- STRIPPEJG SOLUTION Louis P. Worrell, Clairton, Pa., assigner to United States Steel Corporation, a corporation of New Jersey Filed st. 26, 1962, Ser. No. 233,360 Claims. (Cl. 134-201) This invention relates to apparatus useful in determining the weight of coating material on coated sheet metal products.

Thin coatings of tin, zinc, aluminum, and occasionally other suitable metals, are applied to sheet steel as a protection against specic corrosive media to provide products suitable for particular services. The amount of such coating is determined by stripping the protective metal from a known area of sample by means of a suitable solvent, aided in some tests by electrolytic action; the weight of coating is calculated from the volume and chemical analysis of the resulting solution or simply from a loss of weight of the sample. Apparatus used heretofore has required cutting the sample to precise dimensions and the use of stop-off lacquers, waxes or pitches so that only one side of the sample is presented to the action of the stripping-medium. The stop-olf materials must be carefully applied (and removed) if the accurate determinations are to be achieved, and the use of such is a tedious, time-consuming operation which adds considerably to the cost of the tests.

The apparatus of the present invention avoids the necessity for stop-off materials as well as the need for cutting samples to precise dimensions.

The new apparatus is described in detail in the specication and appended drawings wherein:

FIGURE l is a top view of one particular embodiment of the apparatus;

FIGURE 2 is a cross section taken along the lines II-II of FIGURE 1;

FIGURE 3 is a top view of an adaptor which can be used in conjunction with apparatus of FIGURES 1 and 2;

FIGURE 4 is a section taken along the lines IV-IV of FIGURE 3 while;

FIGURE 5 is a cross sectional assembly illustrating use of the adaptor;

FIGURE 6 is the side elevation of a modication of the apparatus for use with samples disposed in a substantially vertical plane and,

FIGURE 7 is a cross section taken along the lines VII-VII of FIGURE 6.

Referring first to the FIGURES 1 and 2, the apparatus comprises-a cylindrical body member 2 having a central bore or cavity 4 extending the length thereof. Concentric with bore 4 and extending upwardly from the bottom face of member 2 is a groove 6 connected by drilled hole 8 to a blind tapped hole 10 extending inwardly of the side wall of 2. A counter bore in the bottom of member 2 forms, with the interior wall of groove 6, a downwardly extending rib 12 to provide a seat adapted to receive and retain an inboardly disposed resilient O-ring 14 and the outer wall of the groove is shouldered to form a similar rib 16 providing a seat for an outboardly disposed O-ring 18. Ribs 12 and 16 terminate in the same plane and are respectively of a length slightly less than the thicknesses of the rings and V14. Pouring lips 19 are formed in the top surfaces of member 2.

The apparatus described above can be used with any sample having dimensions but slightly greater than the diameter of O-ring 16. Apparatus is connected through hole 10 to a suitable vacuum source, it is then placed over the sample and vacuum applied to the groove 6 to compress the O-rings to draw the sample tightly against ribs 12 and 16 to seal the bottom of bore 4. The stripping solution is then poured into the resulting chamber to be decanted therefrom upon completion of the stripping. Release of the vacuum disengages the sample which can then be turned over and the operation repeated on the other side. Body member 2 may be made of any material which is inert to the stripping solution and the O-rings of any suitably resilient material, e.g. neoprene, rubber and the like. A bore 4 about 11/2 in diameter and about 3 long provides ample solution volume and sample surface area for accurate determinations when using any of the common stripping solutions.

The apparatus of FIGURES l and 2 can be adapted for use with samples down to a size but slightly greater than the diameter of O-ring 14 by means of the base plate 20 shown in FIGURES 3 and 4. A circular cavity 22 is provided in the plate 2l) and formed to have an internally projecting rib 24 which serves to support and retain an O-ring 26, the internal diameter of the latter and of rib 24 being just slightly greater than the external diameter of the member 2. Seated in the bottom of the cavity 22 is an O-ring 28 which is of the same or just slightly smaller diameter than O-ring 14 of member 2. As shown in FIGURE 5 the sample is centered over the O-ring 28 and body member 2, with the O-ring 18 removed, is inserted through O-ring 26 so that O-ring 14 bears upon the upper surface of the sample. Application of vacuum to groove 6 holds the assembly into water tight engagement.

In some instances it is necessary to strip the coating from samples lxedly attached in the substantially vertical position. This is readily accomplished by the modilication shown in FIGURES 6 and 7 wherein the body member 2A is a rectangular block having a blind-bore 4A, groove 6A and ribs 12A and 16A formed in a side face 30 thereof. A blind-bore 32 extends downwardly through the top of 2A to join the bore 4A and provide the solution holding cavity. In use, the side face 30 is placed against the vertical sample and vacuum applied through the hole 10A to compress the O-rings (14A and 18A) and hold the apparatus in place. A tapped hole 34 closed by threaded plug valve 36 is provided in the bottom of bore 32 to facilitate draining of the stripping solution.

While I have shown and described certain specific embodiments of my invention it is apparent that modications may be made Without departing from the scope of the appended claims.

I claim:

l. Apparatus for stripping protective coating material from the surface of a at coated product comprising a body member having a solution receiving cavity formed therein and opening in one outer face thereof, a pair of concentric ribs encompassing said opening and extending outwardly from said face, a lirst resilient O-ring disposed outboard around the outer of said ribs, a second resilient O-ring disposed inboard around the inner of said ribs, an annular groove extending into said body member from said face between said ribs and a passageway connecting said groove through the Wall of said body member to a source of vacuum external of said member.

2. Apparatus for stripping protective coating material from the surface of a llat coated product comprising a body member having a cavity formed therethrough to open in two different outer faces of said member, one of said faces comprising a sealing face adaptable to seal against a flat surface of a coated-specimen to be stripped, said sealing face being characterized by a pair of concentric annular ribs encompassing the opening therein and extending outwardly from said face, a rst resilient O-ring disposed outboard around the outer of said ribs,

a second resilient O-ring disposed inboard around the inner of said ribs, an annular groove extending into said body member from said sealing face between said ribs, and a passageway connecting said groove through the wall of said body member to a source of vacuum.

3. The apparatus of claim 2 wherein the faces of the body member containing the cavity openings are disposed at substantially 90 with respect to each other.

4. Apparatus for stripping protective coating material from the surface of a flat coated product comprising a cylindrical body member having a central bore extending the length thereof, a pair of ribs concentric with said bore extending downwardly from the bottom face of said member, a first resilient O-ring disposed outboard around the outer of said ribs, a second resilient O-ring disposed inboard around the inner of said ribs, an annular groove extending into said body member from said sealing face between said ribs, and a passageway connecting said groove through the wall of said body member to a source of vacuum.

5. Apparatus for stripping protective coating material from the surface of a flat coated product comprising a cylindrical body member having a central bore extend- 'i -ing the length thereof, a pair of ribs concentric with said bore extending downwardly from the bottom face of said member, a first resilient G-ring disposed inboard around tbe inner of said ribs, an annular groove extending upwardly into said body member between said ribs, a passageway through the side wall of said body member connecting said groove to a source of vacuum, a base plate having in the top surface thereof a blind-bore adapted to receive the bottom end of said cylindrical body member, a rib disposed intermediately the length of said blind-bore to extend inwardly toward the center thereof, a second resilient O-ring disposed in said blindbore to rest upon the upper surface of said inwardly extending rib in contact with the side wall of the cylindrical body member, and a third resilient O-ring of substantially the same size as the rst mentioned O-ring seated concentric with said blind-bore and in the bottom thereof.

References Cited in the le of this patent UNITED STATES PATENTS 571,017 Reeve Nov. l0, 1896 1,792,606 Richards Feb. 17, 1931 2,067,922 Hothersall Jan. 19, 1937 3,073,727 Mullinex Ian. 15, 1963 

1. APPARATUS FOR STRIPPING PROTECTIVE COATING MATERIAL FROM THE SURFACE OF A FLAT COATED PRODUCT COMPRISING A BODY MEMBER HAVING A SOLUTION RECEIVING CAVITY FORMED THEREIN AND OPENING IN ONE OUTER FACE THEREOF, A PAIR OF CONCENTRIC RIBS ENCOMPASSING SAID OPENING AND EXTENDING OUTWARDLY FROM SAID FACE, A FIRST RESILIENT O-RING DISPOSED OUTBOARD AROUND THE OUTER OF SID RIBS, A SECOND RESILIENT O-RING DISPOSED INBOARD AROUN THE INNER OF SAID RIBS, AN ANNULAR GROOVE EXTENDING INTO SAID BODY MEMBER FROM SAID FACE BETWEEN SAID RIBS AND A PASSAGEWAY CONNECTING SAID GROOVE THROUGH THE WALL OF SAID BODY MEMBER TO A SOURCE OF VACUUM EXTERNAL OF SAID MEMBER. 